will newtown be any different? it's already been ranked the second worst school shooting in american history. virginia tech in 2007 was the worst, 32 people died there. at columbine high school in 1999, 13 people were killed, another two dozen wounded. but since when have school shootings had their own grisly greatest hits list? >> what we see is patterns of one of these incidents inspiring if you will, disturbed people who are already thinking about doing something like that, to do copy cat incidents or to enhance their own incident to make it worse. >> reporter: this even has a name. the wurther effect, according to the former f.b.i. spokesman and now a senior correspondent for cbs news. how do we stop it, can we stop it? >> well, there's a series of chicken and egg questions there. is it the security of the physical premises, is it the gun laws, is it us? >> reporter: adam lanza's mother we've learneds with a gun enthusiast, she owned the guns her son used to kill her and the rest of the newtown victims. will th